Higher-distance commuting varieties. Issue 17 (22nd November 2022)

• Record Type: Journal Article
• Authors: Elyze, Madeleine; Guterman, Alexander; Morrison, Ralph; Šivic, Klemen
• Is Part Of: Linear & multilinear algebra. Volume 70:Issue 17(2022)
• Page Start: 3248
• Page End: 3270
• Publication Date: 2022-11-22
• Subjects: Commuting variety -- commuting distance -- commuting graph; 14M12 -- 15A27; Algebras, Linear -- Periodicals; Multilinear algebra -- Periodicals; 512.505
• DOI: 10.1080/03081087.2020.1834493
• Languages: English
• ISSNs: 0308-1087

Abstract

ABSTRACT: The commuting variety of matrices over a given field is a well-studied object in linear algebra and algebraic geometry. As a set, it consists of all pairs of square matrices with entries in that field that commute with one another. In this paper, we generalize the commuting variety by using the commuting distance of matrices. We show that over an algebraically closed field, each of our sets does indeed form a variety. We compute the dimension of the distance-2 commuting variety and characterize its irreducible components. We also work over other fields, showing that the distance-2 commuting set is a variety but that the higher distance commuting sets may or may not be varieties, depending on the field and on the size of the matrices.